ELO rating reliable

I just got a new software for teaching chess, its called CT-ART, and for those who know this program, can you tell me how reliable is the ELO rating on this software, thank you

The ELO ratings of CT-ART (or any tactical trainer) really are just warm-fuzzies/eye-candy to tell you how "tactically" strong you might be ....  though it is important to ask "relative to what?"

- A real ELO rated player who plays 3+ hr OTB games in a tournament?

- A large test pool of ELO rated players (of all ratings) who went through these 1200+ tactical problems to give the software developer a metric to say "okay, if you are this accurate, you are probably as good in tactics as a 1500-rated player who did just as well" etc.

If it is the latter, then there is some "reliability" to these numbers.

A rating is and only is an indication of your overall playing strength relative to others within a bounded competitive playing field (FIDE, USCF etc.).

Even then, unless you play a large number of these games over time, your "rating" doesn't really reflect your true playing strength at chess.

From my own experience I've just used the tool (which is damn good, btw) for the purposes of training to see tactical shots fast + accurately.  No matter if I got 90% right and have a "tout-worthy" tactical rating of 1800+ ... this is MEANINGLESS to me as I'm only concerned about the  10% I got wrong /what patterns my brain is still missing.

thank you for your time spent on the answer, i have not played much in tournaments, last time it was 1 year ago, and the software rates my tactical ability around 1900 with 85% done right, i was just wondering if those numbers really do tell you the avarage or if they are based on a completely different calculating method, anyway thanx again for your answer

The thing is, even if the ratings are used in the second sense as Shivsky suggests, it doesn't translate that because you can score as well as an 1800 on tactical problems that you'll play at 1800 level. Chess includes a large combination of skills and knowledge, and tactical ability is just one of those parts. Generally, one's game is constrained more by one's weaknesses than it is helped by one's strengths (at least it is in my own experience).